1 /**************************************************************************
2 * Copyright(c) 1998-1999, ALICE Experiment at CERN, All rights reserved. *
4 * Author: The ALICE Off-line Project. *
5 * Contributors are mentioned in the code where appropriate. *
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8 * documentation strictly for non-commercial purposes is hereby granted *
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11 * appear in the supporting documentation. The authors make no claims *
12 * about the suitability of this software for any purpose. It is *
13 * provided "as is" without express or implied warranty. *
14 **************************************************************************/
19 // Generator to simulate beam gas interactions.
20 // At present single interactions are read from an external file.
21 // Several interactions are combined in one event.
22 // By default the vertex is smeared between +/- 20 m
23 // Author: andreas.morsch@cern.ch
25 #include "AliGenBeamGas.h"
27 #include <TParticle.h>
30 ClassImp(AliGenBeamGas)
32 AliGenBeamGas::AliGenBeamGas()
43 //____________________________________________________________
45 AliGenBeamGas::~AliGenBeamGas()
51 //___________________________________________________________
52 void AliGenBeamGas::Init()
55 AliGenExtFile::Init();
59 void AliGenBeamGas::Generate()
63 Float_t polar[3] = {0,0,0};
64 Float_t origin[3] = {0,0,0};
70 while(nInt < fInteractions) {
76 origin[2] = 2. * fOsigma[2] * random[0] - fOsigma[2];
80 Float_t ibeam = (random[1] < 0.5) ? -1. : 1.;
85 Int_t nTracks = fReader->NextEvent();
87 // printf("\n No more events !!! !\n");
88 Warning("AliGenBeamGas::Generate",
89 "\nNo more events in external file!!!\n Last event may be empty or incomplete.\n");
96 for (i = 0; i < nTracks; i++) {
97 TParticle* iparticle = fReader->NextParticle();
98 p[0] = iparticle->Px();
99 p[1] = iparticle->Py();
100 p[2] = iparticle->Pz() * ibeam;
102 Int_t idpart = iparticle->GetPdgCode();
103 Int_t decayed = iparticle->GetFirstDaughter();
104 Int_t doTracking = fTrackIt && (decayed < 0) && (TMath::Abs(idpart) > 10);
105 PushTrack(doTracking,-1,idpart,p,origin,polar,0,kPPrimary,nt);
111 SetHighWaterMark(nt);